Name:	rs_DebtInstrumentUnamortizedDiscountAndDebtIssuanceCost
Namespace Prefix:	rs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of short-term debt and current maturity of long-term debt and capital lease obligations due within one year or the normal operating cycle, if longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19,20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_DebtCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Represents the aggregate of total long-term debt, including current maturities and short-term debt.

No definition available.

Name:	us-gaap_DebtLongtermAndShorttermCombinedAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_LongTermDebtNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Name:	us-gaap_DebtInstrumentAxis=rs_UnsecuredRevolvingCreditFacilityDueSeptember2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_DebtInstrumentAxis=rs_UnsecuredRevolvingCreditFacilityDueApril2018Member
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_DebtInstrumentAxis=rs_UnsecuredTermLoanDueSeptember2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_DebtInstrumentAxis=rs_UnsecuredTermLoanDueApril2018Member
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_DebtInstrumentAxis=rs_SeniorUnsecuredNotesDueNovember2016Member
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_DebtInstrumentAxis=rs_SeniorUnsecuredNotesDue2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_DebtInstrumentAxis=rs_SeniorUnsecuredNotesDueNovember2036Member
Namespace Prefix:
Data Type:	na
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